My Problem:Occasionally, we have users who use an email client to send email from home or even business IPs to the SMTP submission port/they use authetication. The problem arises when the connecting IP is dynamic.Usually these users on dynamic IPs are delivered just fine - and in my inbox. The email client doesn't junk them.But, we have a few that are continually on "Policy Blocklists' spamhaus PBL or similar and this is the only thing I can find wrong with the email. The server delivers to inbox since this isn't a true blacklisted IP, but on many email clients the email gets delivered to the Junk folder - assuming the IP being on the policy list increases likelihood of it being spam?

My fix that isn't working:I am trying to hide the received IP on sent emails from ME users using the SMTP server (in other words only if they authenticate properly on SMTP). If they auth correctly - there is no reason to know or need to investigate the incoming IP in most cases.

Unfortunately, if you turn this option on (Servers/Services/SMTP Properties/Security/"Hide sender IP..") it hides it on ALL incoming emails.

I just want it to hide it on authenticated SMTP users ONLY.

Spamhaus Blurb about being ON PBL list:

Outbound Email Policy of The Spamhaus Project for this IP range:

This IP address range has been identified by Spamhaus as not meeting our policy for IP addresses permitted to deliver unauthenticated 'direct-to-mx' email to PBL users.Important: If you are using any normal email software (such as Outlook, Entourage, Thunderbird, Apple Mail, etc.) and you are being blocked by this Spamhaus PBL listing when you try to send email, the reason is simply that you need to turn on "SMTP Authentication" in your email program settings. For help with SMTP Authentication or ways to quickly fix this problem click here.

See also: http://www.spamhaus.org/faq/section/Spamhaus%20PBL

This would leave me to believe that simply authticating the IP on a given server would fix the problem. Of course it does not. The first received IP on a send is going to be there whether you autheticate or not. Am I missing something?